A researcher at a major hospital wishes to estimate the proportion of the adult population of the United States that has high blood pressure. How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 6%? 267 10 755 378

Respuesta :

Answer:

option d)378

Step-by-step explanation:

Given that a researcher at a major hospital wishes to estimate the proportion of the adult population of the United States that has high blood pressure.

Margin of error should be at most 6% = 0.06

Let us assume p =0.5 as when p =0.5 we get maximum std deviation so this method will give the minimum value for n the sample size easily.

We have std error = [tex]\sqrt{\frac{pq}{n} } =\frac{0.5}{\sqrt{n} }[/tex]

For 98%confident interval Z critical score = 2.33

Hence we have margin of error = [tex]2.33(\frac{0.5}{\sqrt{n} } <0.06\\n>377[/tex]

Hence answer is option d)378

The size of the sample needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 6% is; 376

What is the size of the sample?

We are told that Margin of error should be at most 6% = 0.06

Formula for margin of error is;

M = z√(p(1 - p)/n)

we are given the confidence level to be 98% and the z-score at this confidence level is 2.326

Since no standard deviation then we assume it is maximum and as such  assume p =0.5 which will give us the minimum sample required.

Thus;

0.06 = 2.326√(0.5(1 - 0.5)/n)

(0.06/2.326)² = (0.5²/n)

solving for n gives approximately n = 376

Thus, the size of the sample required is 376

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